Oilfield tubular connections employing standard API threads e.g., 8-round, have been used for many years on tubing and casing. There are certain drawbacks to standard API threads including relatively slow make-up times and a tendency to be weak in tension.
As is well known, in recent years the development of shale formations in the United States for producing both oil and gas has exploded. Indeed, the development of these shale formations has made the United States one of the largest producers of oil and gas in the world and for all intents and purposes has made the United States energy independent. The construction of oil and gas wells in shale formations is difficult. To begin with, a typical well for recovering oil and/or gas from shale formations requires the drilling of a vertical section and a kick off into a lateral or horizontal section. As is known to those skilled in the art, in moving from the vertical section of a well to the lateral section, the threads of a typical oil field tubular go from tension loading to compression loading. These changing forces on the threaded connection lead to instability in the connections resulting in leakage among other problems. In particular, the changing tension to compression forces coupled with make-up torque loads, internal pressure loads, bending loads and torsion loads can render standard API connections unstable, leading to leaks.